ZHCSG71 March 2017 TAS6424L-Q1
PRODUCTION DATA.
- 1 特性
- 2 應用
- 3 說明
- 4 修訂歷史記錄
- 5 Device Comparison Table
- 6 Pin Configuration and Functions
- 7 Specifications
- 8 Parameter measurement Information
-
9 Detailed description
- 9.1 Overview
- 9.2 Functional Block Diagram
- 9.3
Feature Description
- 9.3.1 Serial Audio Port
- 9.3.2 High-Pass Filter
- 9.3.3 Volume Control and Gain
- 9.3.4 High-Frequency Pulse-Width Modulator (PWM)
- 9.3.5 Gate Drive
- 9.3.6 Power FETs
- 9.3.7 Load Diagnostics
- 9.3.8
Protection and Monitoring
- 9.3.8.1 Overcurrent Limit (ILIMIT)
- 9.3.8.2 Overcurrent Shutdown (ISD)
- 9.3.8.3 DC Detect
- 9.3.8.4 Clip Detect
- 9.3.8.5 Global Overtemperature Warning (OTW), Overtemperature Shutdown (OTSD)
- 9.3.8.6 Channel Overtemperature Warning [OTW(i)] and Shutdown [OTSD(i)]
- 9.3.8.7 Undervoltage (UV) and Power-On-Reset (POR)
- 9.3.8.8 Overvoltage (OV) and Load Dump
- 9.3.9 Power Supply
- 9.3.10 Hardware Control Pins
- 9.4 Device Functional Modes
- 9.5 Programming
- 9.6
Register Maps
- 9.6.1 Mode Control Register (address = 0x00) [default = 0x00]
- 9.6.2 Miscellaneous Control 1 Register (address = 0x01) [default = 0x32]
- 9.6.3 Miscellaneous Control 2 Register (address = 0x02) [default = 0x62]
- 9.6.4 SAP Control (Serial Audio-Port Control) Register (address = 0x03) [default = 0x04]
- 9.6.5 Channel State Control Register (address = 0x04) [default = 0x55]
- 9.6.6 Channel 1 Through 4 Volume Control Registers (address = 0x05-0x08) [default = 0xCF]
- 9.6.7 DC Load Diagnostic Control 1 Register (address = 0x09) [default = 0x00]
- 9.6.8 DC Load Diagnostic Control 2 Register (address = 0x0A) [default = 0x11]
- 9.6.9 DC Load Diagnostic Control 3 Register (address = 0x0B) [default = 0x11]
- 9.6.10 DC Load Diagnostic Report 1 Register (address = 0x0C) [default = 0x00]
- 9.6.11 DC Load Diagnostic Report 2 Register (address = 0x0D) [default = 0x00]
- 9.6.12 DC Load Diagnostics Report 3 Line Output Register (address = 0x0E) [default = 0x00]
- 9.6.13 Channel State Reporting Register (address = 0x0F) [default = 0x55]
- 9.6.14 Channel Faults (Overcurrent, DC Detection) Register (address = 0x10) [default = 0x00]
- 9.6.15 Global Faults 1 Register (address = 0x11) [default = 0x00]
- 9.6.16 Global Faults 2 Register (address = 0x12) [default = 0x00]
- 9.6.17 Warnings Register (address = 0x13) [default = 0x20]
- 9.6.18 Pin Control Register (address = 0x14) [default = 0x00]
- 9.6.19 AC Load Diagnostic Control 1 Register (address = 0x15) [default = 0x00]
- 9.6.20 AC Load Diagnostic Control 2 Register (address = 0x16) [default = 0x00]
- 9.6.21 AC Load Diagnostic Impedance Report Ch1 through CH4 Registers (address = 0x17-0x1A) [default = 0x00]
- 9.6.22 AC Load Diagnostic Phase Report High Register (address = 0x1B) [default = 0x00]
- 9.6.23 AC Load Diagnostic Phase Report Low Register (address = 0x1C) [default = 0x00]
- 9.6.24 AC Load Diagnostic STI Report High Register (address = 0x1D) [default = 0x00]
- 9.6.25 AC Load Diagnostic STI Report Low Register (address = 0x1E) [default = 0x00]
- 9.6.26 Miscellaneous Control 3 Register (address = 0x21) [default = 0x00]
- 9.6.27 Clip Control Register (address = 0x22) [default = 0x01]
- 9.6.28 Clip Window Register (address = 0x23) [default = 0x14]
- 9.6.29 Clip Warning Register (address = 0x24) [default = 0x00]
- 9.6.30 ILIMIT Status Register (address = 0x25) [default = 0x00]
- 9.6.31 Miscellaneous Control 4 Register (address = 0x26) [default = 0x40]
- 10Application and Implementation
- 11Power Supply Recommendations
- 12Layout
- 13器件和文檔支持
- 14機械、封裝和可訂購信息
12 Layout
12.1 Layout Guidelines
The pinout of the TAS6424L-Q1 was selected to provide flowthrough layout with all high-power connections on the right side, and all low-power signals and supply decoupling on the left side.
Figure 65 shows the area for the components in the application example (see the Typical Applications section).
The TAS6424L-Q1 EVM uses a four-layer PCB. The copper thickness was selected as 70 µm to optimize power loss.
The small value of the output filter provides a small size and, in this case, the low height of the inductor enables double-sided mounting.
The EVM PCB shown in Figure 65 is the basis for the layout guidelines.
12.1.1 Electrical Connection of Thermal pad and Heat Sink
For the DKQ package, the heat sink connected to the thermal pad of the device should be connected to GND. The heat slug must not be connected to any other electrical node.
12.1.2 EMI Considerations
Automotive-level EMI performance depends on both careful integrated circuit design and good system-level design. Controlling sources of electromagnetic interference (EMI) was a major consideration in all aspects of the design. The design has minimal parasitic inductances because of the short leads on the package which reduces the EMI that results from current passing from the die to the system PCB. Each channel also operates at a different phase. The design also incorporates circuitry that optimizes output transitions that cause EMI.
For optimizing the EMI a solid ground layer plane is recommended, for a PCB design the fulfills the CISPR25 level 5 requirements, see the TAS6424L-Q1 EVM layout.
12.1.3 General Guidelines
The EVM layout is optimized for low noise and EMC performance.
The TAS6424L-Q1 has an exposed thermal pad that is up, away from the PCB. The layout must consider an external heat sink.
Refer to Figure 65 for the following guidelines:
- A ground plane, A, on the same side as the device pins helps reduce EMI by providing a very-low loop impedance for the high-frequency switching current.
- The decoupling capacitors on PVDD, B, are very close to the device with the ground return close to the ground pins.
- The ground connections for the capacitors in the LC filter, C, have a direct path back to the device and also the ground return for each channel is the shared. This direct path allows for improved common mode EMI rejection.
- The traces from the output pins to the inductors, D, should have the shortest trace possible to allow for the smallest loop of large switching currents.
- Heat-sink mounting screws, E, should be close to the device to keep the loop short from the package to ground.
- Many vias, F, stitching together the ground planes can create a shield to isolate the amplifier and power supply.
12.2 Layout Example
Figure 65. EVM Layout
12.3 Thermal Considerations
The thermally enhanced PowerPAD package has an exposed pad up for connection to a heat sink. The output power of any amplifier is determined by the thermal performance of the amplifier as well as limitations placed on it by the system, such as the ambient operating temperature. The heat sink absorbs heat from the TAS6424L-Q1 and transfers it to the air. With proper thermal management this process can reach equilibrium and heat can be continually transferred from the device. Heat sinks can be smaller than that of classic linear amplifier design because of the excellent efficiency of class-D amplifiers. This device is intended for use with a heat sink, therefore, RθJC will be used as the thermal resistance from junction to the exposed metal package. This resistance will dominate the thermal management, so other thermal transfers will not be considered. The thermal resistance of RθJA (junction to ambient) is required to determine the full thermal solution. The thermal resistance is comprised of the following components:
- RθJC of the TAS6424L-Q1
- Thermal resistance of the thermal interface material
- Thermal resistance of the heat sink
The thermal resistance of the thermal interface material can be determined from the manufacturer’s value for the area thermal resistance (expressed in °Cmm2/W) and the area of the exposed metal package. For example, a typical, white, thermal grease with a 0.0254 mm (0.001 inch) thick layer is approximately 4.52°C mm2/W. The TAS6424L-Q1 in the DKQ package has an exposed area of 47.6 mm2. By dividing the area thermal resistance by the exposed metal area determines the thermal resistance for the thermal grease. The thermal resistance of the thermal grease is 0.094°C/W
Table 41 lists the modeling parameters for one device on a heat sink. The junction temperature is assumed to be 115°C while delivering and average power of 10 watts per channel into a 4 Ω load. The thermal-grease example previously described is used for the thermal interface material. Use Equation 1 to design the thermal system.
Table 41. Thermal Modeling
| Description | Value |
|---|---|
| Ambient Temperature | 25°C |
| Average Power to load | 40W (4x 10w) |
| Power dissipation | 8W (4x 2w) |
| Junction Temperature | 115°C |
| ΔT inside package | 5.6°C (0.7°C/W × 8W) |
| ΔT through thermal interface material | 0.75°C (0.094°C/W × 8W) |
| Required heat sink thermal resistance | 10.45°C/W ([115°C – 25°C – 5.6°C – 0.75°C] / 8W) |
| System thermal resistance to ambient RθJA | 11.24°C/W |